Lithographic apparatus and device manufacturing method

Abstract

A lithographic apparatus comprises an illumination system for supplying a beam of radiation, a patterning arrangement incorporating an array of individually controllable elements for imparting a pattern to the beam cross-section, a substrate table for supporting a substrate, and a projection system incorporating a microlens array for projecting the beam onto a target portion of the substrate. An error compensator is provided for supplying error correction values for compensating for the effect of positional errors in the microlens array, and a grey scale modulator is provided for supplying drive signals to controllable elements of the patterning arrangement in dependence on the error correction values in order to compensate for the effect of positional errors in the microlens array by varying the intensity of some parts of the pattern relative to other parts of the pattern.

Description

BACKGROUND[0001]1. Field of the Invention[0002]The present invention relates to a lithographic apparatus and a device manufacturing method.[0003]2. Related Art[0004]A lithographic apparatus is a machine that applies a desired pattern onto a target portion of a substrate. The lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs), flat panel displays, and other devices involving fine structures. In a conventional lithographic apparatus, a patterning means, which is alternatively referred to as a mask or a reticle, can be used to generate a circuit pattern corresponding to an individual layer of the IC (or other device), and this pattern can be imaged onto a target portion (e.g., comprising part of one or several dies) on a substrate (e.g., a silicon wafer or glass plate) that has a layer of radiation-sensitive material (e.g., resist). Instead of a mask, the patterning means can comprise an array of individually controllable elements that gene...

AI Technical Summary

Benefits of technology

[0010]According to one embodiment of the present invention, there is provided a lithographic apparatus comprising an illumination system, a patterning arrangement, a projection system, an error compensator, and a gray scale modulator. The illumination system supplies a beam of radiation. The patterning arrangement patterns the beam. The projection system projects the beam onto a target portion of a substrate. The error compensator supplies error correction values for compensating for the effect of errors in the projection system. The grey scale modulator supplies drive signals to the patterning arrangement based on the error correction values in order to compensate for the effect of errors in the projection system by varying the intensity of some parts of the pattern.

[0011]In accordance with one embodiment of the present invention, there is provided a device manufacturing method comprising the following steps. Imparting a pattern to a beam using an adjustable patterning arrangement. Projecting the patterned beam of radiation onto a target portion of a substrate. Providing error correction values for compensating for the effect of errors in the projection system. Supplying drive signals to the patterning arrangement based on the error correction values in order to compensate for the effect of errors in the projection system by varying the intensity of some parts of the pattern.

Problems solved by technology

This small tolerance can lead to errors.

However, it is extremely difficult to manufacture MLA's that are capable of generating image spots having position errors of less than about 20 nm, and currently there are no techniques available to permit correction of position errors in the XY plane to the required level of accuracy.

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